Junction box for rope thimble



April 16, 1946.

E. H. BORGELT 2,398,403

JUNCTION BOX FOR ROPE THIMBLE Filed Sept. 20 1944 2 Sheets-Sheet 1INVENTOR. v v v 12/[19/9/80/96427 ATTORNEY April 1946- I BORGELT2,398,403

JUNCTION BOX FOR ROPE THIMBLE Filed Sept. 20 1944 2 Sheet-Sheet 2 v 0 OI INVBVTOR. 17/141296! fl/96:17

ATTORNEY Patented Apr. 16, 1946 JUNCTION BOX FOR ROPE THIMBLE Elmer H.Borgelt, Dayton, Ohio; assignor to the Government of the United Statesof America, as represented by the Secretary of War Application September20, 1944, Serial No. 554.932

(Granted undr the act of March 3, 1883, as amended April 30, 1928; 3-700. G. 757) 4 Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to me ofany royalty thereon.

The invention to be hereinafter described relates to a thimble blockjunction box for ropes.

In towing, especially airplane towing, there are many difiicultiesencountered in the electrical connections between the conductors carriedby the rope and the object to which the conductor is connected at one orthe other end. Some of these are due to the difference in elongationbetween the conductor and the tow rope carrying the conductor, which iswell understood. Various provisions have been made to compensate thisdifference, with considerable success. Ther still remain evidentdiificulties at and near the thimbles and adjacent connections. In use,especially in towing use with airplanes, the thimble and all partsimmediately carried thereby or closely connected thereto receive verysevere punishment. The tow rope is regularly dropped as the tow is endedand falls full weight from a considerable height.

Oneof the most serioustroubles is due to excessiv strain on theconductor in pulling out the connection when the tow rope isdisconnected. Either the usual plug-and-socket coupling is damaged orthe conductor is torn from the coupling or the conductor is otherwisedamaged. One protective arrangement against this is to provide. slack inthe conductor adjacent the thimble, with a. short. chain or the likefrom the thimble to the respective plug-and-socket memher, the chainbeing of such length as. to pull the. member before strain falls on theconductor. That still leaves the plug-and-socket member swinging on thefree end of the conductor. When damaged by the fall, as is veryfrequent, it. must be removed and a new one connected. This may not beserious at a near base but, even there it requires appreciable time.

The present invention eliminates or greatly minimizes th above and otherobjections and provides. a simple efiicient, compact and durablejunction box carried by the thimble and providing speedy and eificientconnections for renewing the damaged plug-and-socket-member.

In. order to more clearly disclose the construction, operation and useof the invention reference. should be had to the accompanying drawingsforming. part of the present application.

lik reference characters designate the same parts in the differentviews.

In thedrawings:

Fig. 1 is aside elevation of a tow connection as at present used;

Fig. 2 is a like view showing the invention applied;

Fig. 3 is a view similar to Fig. 2, with the remote box wall removed;

Fig.4 isatop plan view of Fig. 2;

'Fig. 5 is a cross section on line 5-'.i of Fig 2; and

Fig. 6 is a plan view of the inside of one of the box walls, removed.

The present type is shown, as in Fig. 1, purely for purposes ofcomparison and needs no further description.

As shown in the drawings, the invention has been designed, proportionedand constructed to be received and fit completely within the loop of theroughly pear-shaped or U-shaped looped thimble of the usual tow rope.The housing, casing, chamber or box so constructed, arranged ordisposed, together with the thimble provides good reliable protectionfor the contacts or junction elements or connections to the conductorcarried by the tow rope.

Preferably, two metal blocks l of complementary construction are used.They are,

roughly, pear-shaped or approximately eggshaped in outline. They are ofapproximately the same minimum peripheral measurementas the minimumperipheral measurement of the inner wall or loop of the thimble 2. Eachblock is recessed as at 3 to provide one part or section of a chamber,box or the like to contain the desired electrical connections; Eachblock I is also provided with a peripheral flange 4 of concave crosssection adapted, when in operative position, to fit snugly on or nestwith the cooperating wall of thimble 2. In the construction shown, thetwo assembled flanges 4 approximately span, bridge, seat or embrace thead- Jacent cooperating half of thimble 2. The blocks I are positivelyand efliciently secured in operative position by connecting rods 5passed through one block and threaded into the other.

Any other suitable connecting means may be used. The blocks, assembledand drawn together in this way, are securely clamped in place within theloop of the thimble. The edges of the thimble form a good continuous andeflicient protection to the box. The assembled. blocks, it will benoticed, do not. extend" or project ap- Throuahout the several figures-.0: the l0 preciably beyond the: thimble in. any direction In effect, thestructure is a rigid, shallow box or chamber having the same outline asthe inner wall of the thimble 2 and having a maximum thicknessapproximately equal to that of the thimble tube providing the necessaryor desired chamber or box, room or space, amply protected against allprobable shock or abuse. Incidentally, this box uses otherwise wastespace. An important consideration is that while, itself, being bracedand supported by the thimble, it also very strongly braces that samethimble.

At the large end each block is provided with a notch 6, the notch of oneblock aligning with that of the other to freely receive the usual link,eye or the like by which the tow rope end is regularly connected to therespective plane. The opposite end of each block is provided with anaxially disposed semi-cylindrical or concave throat groove I leadingoutwardly from recess 3. These two grooves, in operative position, alignto provide a cylindrical throat outlet.

It should be noted that, in assembled position, the throat groove I isin approximate alignment with and continuation of the longitudinal axisor center of the adjacent section of the tow rope leading to thethimble.

Usually, the conductor cable carried by the tow rope comprises threeconductors. While that is usual, it is not a definite limitation, as iswell understood. Because such is the usual arrangement, three conductorsare shown in this case.

Within the box, on the wall of one recess, are provided three bindingposts 8, one for each of tie usual three conductors of the tow rope.

Adjacent binding posts 8 are a second series of three binding posts 9,for a purpose to be later disclosed.

In operation, the three conductors are led in through the throat I and,each provided with the usual terminal, connected in usual manner to oneof the binding posts 6. Ample slack is provided to compensate for thepredetermined, calculated, elongation of the adjacent section of theparticular type of tow rope. A closely coiled strong spring It providesan adequate guide and ample protection for the conductors from the towrope, through throat 1, into recesses fiend to a point close to thebinding posts 8. It provides a complete shield and protection or armorbetween the conductors and the throat I. As shown, it extends outwardlybeyond the throat I to the adjacent splice end. At this point, thespring is securely anchored, or connected to the tow rope by a loop I!which is simply branched off from and extended around and about the twoadjacent branches of the loop. So, as the rope elongates, under tensionof a tow, for instance, the spring clongates correspondingly and theprovided slacl: in the conductor pays out. And, as the tension andelongation decrease the spring contracts and the slack returns. Thus,the spring It} is-an armored protection and guide for the conductors.

The above provides a solid, substantial, eificient and compact completeunit with all electrical connections amply protected against allprobable shock or damage.

In order to continue the conductor connections from the junction box tothe usual plug-andsocket-member, a short conductor section I2 having theusual three conductors, is provided. One end of this is connected inusual and well known manner to the plug-and-socket member while.

a suitable bore or opening through one of the blocks I, adjacent theposts 9, the usual slack being allowed and a short wire rope I4 beingprovided between block I and the plug-and-socket member to preventinjury to section I2 in disconnecting.

As the tow rope is dropped or as it is dragged, as is very frequentlythe case, there is a tendency to scrape or scoop sand and dirt throughthroat I to the interior where it may cause trouble. To prevent or, atleast, minimize that difllculty, a guard l5 in the form of a washer,ring or the like of rubber or other suitable ma terial is used.

These short sections I2, a foot or so long, with plug or socket may beeasily and quickly attached and detached with efficient connections andin extremely little time. This may be done anywhere with equal ease. Ifthe plug or socket member or the section I2 becomes damaged it is onlynecessary to loosen the screws of the binder posts 9, pull out theterminals of a new section I2 and tighten the same screws. Of course,the new wire rope I4 would also be connected.

With this arrangement the two rope is a complete and entire unit initself, while section I2 is another complete unit cooperating with butseparable from the tow rope. The two, however, in assembled relation,are essential for communication between a tow plane and its tow or inany analogous relation where communication is involved.

It is thought that the construction, operation and use of the inventionwill be clear from the preceding detailed description.

Many changes may be made in the construction, arrangement anddisposition of the various parts of the invention within the scope ofthe claims without departing from the field of the invention and it ismeant to include all such within this application wherein only onepreferred form has been shown purely by way of illustration and with nothought or intention to, in any degree, limit the invention thereby.

Having thus disclosed my invention, what I claim and desire to protectby Letters Patent is:

1. In combination, a looped thimble, a junction box within the loop ofsaid thimble, supported by said thimble, bracing said thimble outwardlyfrom within and braced inwardly by said thimble, means within said boxfor connecting conductors thereto, conductors leading into said box tosaid connecting means, an extensible armor surrounding said conductorsand means securing said box in operative position.

2. In combination, a looped thimble, a junction box within the loop ofsaid thimble and disposed approximately within the plane of saidthimble, said junction box comprising a pair of chambered complementaryblocks having an outside dimension substantially that of thecorresponding inside dimension of said loop and provided with clampingflanges embracing the corresponding thimble walls, when in assembledrelation, and means for drawing said plates into operative clamping andoutwardly thimble bracing position with the box shielded by said thimbleloop.

3. In combination, a looped thimble, a junction box within the loop ofsaid thimble, supported by said thimble, bracing said thimble outwardlyfrom within and shielded by said looped thimble, said junction boxcomprising a pair of chambered complementary blocks having an outsidedimension substantially that of the corresponding inside dimension ofsaid loop and provided with clam'p said thimble, bracing said thimbleoutwardly from within and shielded by said looped thimble, said junctionbox comprising a pair of cooperating plates one having a junction boxcavity, said plates having outside dimensions substantiallycorresponding to the cooperating inside dimensions of said loop andprovided with clamping flanges embracing the corresponding thimblewalls, when in assembled relation, and means for drawing said platesinto operative clamping position.

ELMER H. BORGELT.

